This is me over here trying to figure out why y’all are getting rid of carbon buildup…
Matthew, can you please explain? I am not understanding the pro and cons of this.
More carbon build up = less room in the combustion chamber.
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Idk man, carbon build up all over my valve seats and ports surely cant be good for air flow …
Clean the seats and the inside of the ports. Leave the rest. The combustion chamber area is what you leave alone.
“Compression is the holy grail.” ~Al Nunley
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Man, I love a good Al Nunley quote. Keep that man’s legacy alive.
“If the data doesn’t support your theory, get a new theory.” -Al Nunley
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He was a hard-headed fella and didn’t always know how to internet, but man what a blessing to have someone from that era of racing actively participating in this forum.
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Also wanted to interject that as an innocent 2T bystander, this whole convo makes KZ seem simple and easy by comparison 
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People just like to make it harder than it is. 
We’re racing glorified generator engines.
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This is the truth here. There is not a 206 race in the world, even Grand Nationals, where the race is decided by that 0.1 hp. 99 drivers out of 100 cannot feel the difference in 0.3 hp, let alone 0.1hp.
And to be clear, we are probably talking about 0.05hp.
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My leakdown has to hit well into double digits before my lap times are altered from engine issues.
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@CrocIndy Wow, really? Double digit???
@fatboy1dh I had the 1 out of 100 that would notice. 
My son would come off complaining when it was above 3% and I could see it on the watch at 5%. I wonder if his size and driving style amplified the impact? I just know we practiced and raced a bunch and I definitely learned to trust him when he said it was flat…would immediately check carb at track and if that didn’t help would check leak down back at the shop after. And dang if that kid wasn’t right most of the time…
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Very cool. You guys must win a lot of races out there!
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Only his first full year last year. Far from dominant and off of the fastest guys most weekends. Managed 3 W’s on the season, 1 TSRS podium and a handful of club podiums, with a 7th on the year in TSRS.
I think his size made him super sensitive to the power relative to peers. That poor LO was trying to push a sail down the straights with his head sticking up above everyone. 
I was just trying to eliminate his ability to place blame anywhere else. Most times we were off a touch on setup or he would overdrive a little. With his height, that matters way more than a 3% leakdown…but try telling a 16 year old that. 
Just remember this famous quote by @tjkoyen
I’m going to make a few stickers with this on it so I can pass it out to the Karens every time I pass tech and they are still complaining because I waxed the field (this pompous confidence is for comedic effect only)
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Lemme know if you have ideas for how that would look and I could help make/edit this better
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Maybe worth pondering where the leakage is coming from too… rings vs valves.
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We had 1 motor running 1-1.5% through the block and another than ran 2% through the block. That was how I arrived at 2% on the block as my tear-down bogey. If I had a head with no bubbles, and no audible leakage, I would get the above numbers with it on the block. I also swapped heads between blocks.
Spent way way too much time on it…
I know of 1 race we were off on the motor (float sticking in left turns only, fine in pits) and it cost him the weekend. But only 1 out of 20+ weekends last year.
Most kids and even some adults will get faster when you just tell them you did something without even doing it.
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